The mounting and maintenance of traffic signals on highways is regulated by the traffic code of the jurisdiction having control over the highway. In most instances the codes require at least one signal at the side of the highway and at least one signal over the travelway of the highway. Due to accidents or oversize loads, the signals frequently are damaged or are knocked askew and require periodic adjustment and/or replacement and repair. Furthermore, when signals are inoperative for a prolonged period, most codes require the signals to be bagged or adjusted to make it obvious that they are not functioning for control purposes, for example by facing the signal housing so that the lenses do not confront the traffic.
Particularly with directional lenses, signals must be accurately aimed so that they may be seen by the approaching traffic at a sufficient distance from the signal to permit safe stopping of the traffic. The aiming of the signals is particularly significant when the approach to the signal is at a steep grade or on a curve.
Adjustable mounting assemblies have been available for many years, as evidenced by U.S. Pat. Nos. 3,586,280; 3,764,099; 3,977,641; 4,010,925 and 4,148,456. A major drawback of these prior mounting brackets is the need for two mechanics at the signal housing in order to effectively adjust the housing to meet the requirements of the particular installation.